Where do hurricanes occur?

Hurricanes or tropical cyclones form in seven distinct basins around the world. Some hurricane formation basins are much more active than others. Some tropical cyclone basins also have conditions in which tropical cyclones may occur over longer periods during the year. Most tropical cyclones form from a disturbance in the monsoon trough. The north Atlantic basin is considerably different, as the majority of hurricanes form from easterly waves originating from Africa.

Hurricanes and typhoons only can form over large basins of warm water such as an ocean or sea. This is due to the fact that they need a large amount of energy which is supplied by the heat from the warm ocean waters evaporating into the atmosphere. Hurricanes also occur at least several degrees away from the equator. This is because the Coriolis force is too weak at the equator to generate spin for the hurricane to develop.

Hurricane and tropical cyclone formation basins

North Atlantic Ocean Hurricane season: June 1 - November 30. The most active period runs from about mid August through the latter part of October. During this peak hurricanes can form in the Atlantic ocean, Gulf of Mexico or Caribbean Sea. Locations that may be affected are the Caribbean, Bermuda, Central America including eastern Mexico, the eastern and Gulf coasts of the United States, and eastern Canada. Many of the hurricanes and tropical storms in this area move around the western periphery of the Bermuda high taking them east of the U.S. east coast. Most U.S. landfalling hurricanes occur when the Bermuda high is stronger allowing for the hurricanes to take a farther west track.

Eastern North Pacific Ocean Hurricane season: May 15 - November 30. This is the second most active region for tropical cyclones in the world. The hurricanes and tropical storms that form in this area mostly move into the open eastern Pacific Ocean. They can also affect western Mexico and the southern Baja. Recently this was seen as Hurriance Odile hit the southern Baja. Sometimes after developing they can move west and many days later affect Hawaii.

Northwest Pacific Ocean Typhoon season: All year. This is the most active basin in the world. Most typhoons form between July through November. The tropical cyclones that form here can affect the Philippines, Guam, southeast Asia (including China and Taiwan), and Japan. This basin produced the strongest tropical cyclone on record - Typhoon Tip in 1979.

Bay of Bengal / Arabian Sea Severe Cyclonic storm season: April 1 - December 30. This basin has a double maximum because of the monsoon trough moving through at two different times of the year. Maximums tropical cyclone activity occurs from mid April through May and from mid September through mid December. This basin is know to produce tropical cyclones that can cause severe flooding resulting in many fatalities.

Southeast Indian Ocean Severe Tropical Cyclone Season: October 15 - May. These tropical cyclones may affect northern and western Australia. This basin has a double maximum in mid January, and mid February through early March.

Southwest Indian Ocean Tropical Cyclone Season: October 15 - May 15. These tropical cyclones may affect Madagascar and southeastern Africa. A double maximum occurs in mid January and mid February through early March.

When is hurricane season?

Hurricane season - north Atlantic oceanHurricane season in the north Atlantic Ocean (including the Gulf of Mexico and Caribbean Sea) is from June 1 through
November 30. Tropical cyclones occasionally form out of this time period, but not very often.

Hurricane season - eastern north Pacific oceanIn the eastern north Pacific, hurricane season is slightly longer and lasts from May 15 through November 30.

If you consider all
of the world's oceans, September is the most active month on average for tropical cyclones and May is the least active.